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By: Karl Baron

Triathlon Interval Training Explained


Training for a triathlon wouldn’t be very exciting if all you did was swim, bike, and run either hard or easy for an extended period of time to increase performance. While there is a time and a place to train relatively easy for a long duration (i.e. zone 2 aerobic workout) or hold a certain pace or heart rate (i.e. tempo workout), to truly improve as an athlete and push the envelope of your performance you need to train with intervals.

Intervals are one of the fastest ways to improve performance and weather you’re aware of it or not your current workouts could be considered interval training. For example almost all endurance workouts involve (or at least should involve) a warm-up, a main-set, and a cool down. In this basic model the main-set is the interval. However, in this article we will discusses interval training that involves several different intervals at a certain heart-rate, power, or pace followed by a rest period.

As seen in Top 10 Indoor Trainer Bike Workouts, one of my favorite bike workouts is what I call 5×5 hill climbs. This workouts looks like this:

Warm-up: 20min Gradually increasing effort

Main-set: 5x5min Z4-5 intervals (sitting and standing) hill climbs. 3 minute recovery between sets.

Cooldown: 30min Z2

As you can the workouts above involve holding a difficult effort in Zone 4-5 for 5 minutes. Followed by a 3 minute  rest period. Even if you are competing a half-ironman which is predominantly raced in Zone 3 or an ironman which is predominantly raced in Zone 2. A workout like this can build a significant amount of muscular endurance needed to get you to the finish line.

While almost any triathlete no matter the distance can benefit from the workout above, the intervals you use in your training should vary week to week to challenge your body, and be based around you, your goals, available time to train, and the distance of triathlon you are competing in.


Train solo: Intervals are difficult to complete with a group or even a training partner. Consider doing running and cycling intervals away from traffic and other distractions where you can really focus on the workout. I personally found intervals are the best time to listen to music when trianing.

Don’t go out to fast: Even intervals as short as 30 seconds can be ruined if start them too fast. Even though it may feel like you’re holding back, build into each interval so you don’t blow up at the end (just like in a race).

More is not better: While it’s true that interval training is one of the best ways to increase performance, more intervals is not always better. Remember intervals are for training not racing, don’t overdo it.

Don’t do intervals when tired: One of the fastest ways to get injured is to do hard intervals when tired, sick, or under emotional stress. If you’re not feeling good during an interval workout, don’t be afraid to stop as you might be causing more harm than good.

If you’re confused about interval training or have any questions/comments please leave them in the comments section below.

About Brad Haag

Brad is a certified USAT triathlon coach, a certified USAC cycling coach, and a certified NCSF personal trainer. Brad specializes in coaching endurance and warrior class athletes to peak performance. He can be found at HaagsAthletics.com.

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